This 2003 report was commissioned by Shell and written by outside consultants. Since it was first leaked, Shell has not disputed the document’s authenticity, but has said it strongly disagrees with some of the report’s conclusions. This copy, obtained by National Public Radio, appears to have had some language deleted. … The consultants warned that, without big changes to how the giant company works with the government and the communities of the delta, a discontent delta population could drive Shell out of the oilfields by 2008.

This is a form of political peaking. Nigeria can produce at current rates for years or decades, but political factors might prevent this.